It is mandatory to file financial statements that use XBRL (eXtensible Business Reporting Language) documents to the Financial Services Agency. XBRL documents are the documents that are described in an XBRL that is a report description language based on an XML (eXtensible Markup Language) with regard to, for example, financial accounting statements. Elements (XBRL elements) that are used in XBRL documents have a hierarchical relationship, and the hierarchical relationship is indicated by using a hierarchical document. A company needs to file a financial statement that uses an XBRL document and, before filing it, generates an XBRL document in which each document item included in the financial statement that is a word processing document is related to each element used in the XBRL document.
Furthermore, there is a disclosed technology of a mapping engine for relating each document item of a text document to each element of a hierarchical document. With this technology, the mapping engine receives an input of each document item of a text document in order in accordance with a predetermined relationship and retrieves the hierarchical document's element that corresponds to the document item for which an input is received.
Patent Document 1: Japanese Laid-open Patent Publication No. 2003-316765
However, the above-described technology has a problem in that, when an XBRL document is generated from a financial statement that is a text document, it is sometimes difficult to correctly map a document item of the text document to an element of the hierarchical document. Specifically, as it is assumed that a document item of the text document is related to an element of the hierarchical document on a one-to-one basis, it is difficult to handle cases on a one-to-N basis. Specifically, if a single document item of the text document is related to N elements of the hierarchical document, it is difficult for the mapping engine to correctly map the document item to an appropriate element of the hierarchical document.
FIG. 12 to FIG. 14 are diagrams that illustrate an example in which it is difficult to correctly map a document item of a text document to an element of a hierarchical document. FIG. 12 is a diagram that illustrates an example of each document item of a financial report and its document item value. FIG. 13 and FIG. 14 are diagrams that illustrate an example of the relationship among XBRL elements of the hierarchical document. A mapping engine is capable of mapping the single document item “reporting period” illustrated in FIG. 12 to “reporting period” of the hierarchical document illustrated in FIG. 13. However, with regard to “reporting period” of the hierarchical document illustrated in FIG. 14, there are “stage”, “start date”, and “end date” on the next hierarchy below. Specifically, as the single document item is related to the three elements, it is difficult for the mapping engine to correctly map the single document item “reporting period” illustrated in FIG. 12 to “reporting period” of the hierarchical document illustrated in FIG. 14.